can you give me a brief decription on how hondas engage in vtec?uhh like what does the engine do to engage or what happens? cause im trying to explain it to some of my domestic friends ,ive tried to search but maybe i type the wrong things in ,thanks


[Modified by accord5speed, 11:13 PM 11/27/2002]

 

VTEC honda engines have 2 Camshaft profiles.
One for good fuel economy and high torque for easy drivability and another cam lobe for performance.

At a predermined RPM, the motor switchs from 1st lobe to second lobe and vice versa.

You basically get the best of both worlds by having and engine that can be fuel efficient and powerful at the same time.

This is the basic VTEC function. Among the honda engines, there are different "Levels" of vtec.

On vtec-e motors, cam profiles are switching from Low-emission, extremely good fuel economy to "normal" mode.

On performace motors (like the DOHCs), the cam profiles are from an "average" cam profile to an aggressive one. This is why some honda motors(b-series) have close to 100hp/liter output.






[Modified by JD_B18CDX, 6:33 PM 11/27/2002]

 

Some VTEC motors have VTEC only on the intake side, but others like the B16, GSR, and Type-R use VTEC on both the intake and exhaust sides.

 

so the lobes determine when you engage in vtec?and when you floor in say a gsr that hits vtec at 4400 what gives it that boost power you know like does the engine just take in more air and fuel or?

 

http://www.howstuffworks.com/question229.htm
it has diagrams

 

No. Ultimately the ECU determines when to engage vtec.

Basically...

 

Without a good working knowledge of internal combustion engines, VTEC is kind of hard to understand. Basically it is like having two camshafts in your engine (or 4 in DOHC). Normally you run on the small, low performance cam. When you hit a certain rpm the ECU operates a solenoid and "turns on" the high performance cam. The mechanism that actually does this stuff is kind of hard to grasp if you don't understand how camshafts, rocker arms, and valves operate, but you should get the idea.